[smackay]

One thing to consider also is a society's ability to change. Rapid industrialization and urbanization were hugely disruptive but were probably manageable, though it took some time to solve all the problems. With people living longer and job often requiring many years of education and training in order to become proficient in a given career choice, the changes over the next 50 years or so might be harder to absorb.

Software development is probably a decent model of what's coming for the rest of the population. Rapid technological change is already reducing the career expectancy of programmers to about 10 years before moves into management or consulting are considered necessary. The cost is that a lot of expertise is lost and the results are often inefficient with many wheels getting re-invented.